A look at the knowns _ and many unknowns _ surrounding the death of Freddie Gray in Baltimore

BALTIMORE – A week and a half after 25-year-old Freddie Gray died, there are still many unanswered questions about the explosive case. A look at some of the knowns and unknowns:

WHY DID POLICE STOP HIM?

Police say they went after him after he fled at the sight of an officer in a drug-infested neighborhood. Why he ran is anyone's guess. Police say they later found a switchblade in his pocket.

During the arrest, officers on bicycles chased him down, pinned him to the sidewalk and then lifted him and took him, his legs dragging on the ground, to a police van. He pleaded for an inhaler during the arrest and asked repeatedly for medical help during the half-hour ride to the station. He died a week later.

WHAT WAS THE CAUSE OF DEATH?

Police say Gray died of a "significant spinal injury." An attorney for the family says his spine was "80 percent severed in the neck area." An autopsy has been done, and while the findings have not been released, police say no bodily injury was evident during the post mortem and no limbs were broken.

SO HOW AND WHEN DID THE INJURY HAPPEN?

That's the big question. It's not clear whether he got hurt during the arrest, the ride, or both. Police say he was in leg irons and handcuffs in the van but was not belted in, a violation of policy. That has raised suspicions that Gray was deliberately taken on a "rough ride" to teach him a lesson and was injured when he got thrown around the back of the vehicle.

WHO KNOWS WHAT WENT ON INSIDE THE VAN?

Police say they have interviewed a second, unidentified man who was in the van, and he said the driver wasn't driving erratically. Police say this man didn't see anyone harm Gray but heard Gray "thrashing about."

WHAT ABOUT THE OFFICERS INVOLVED?

Police have suspended six in the meantime, and five of them have given statements to investigators. The sixth declined to do so. All of them joined the force between 1997 and 2012.

WHERE DOES THE CASE GO FROM HERE?

Baltimore police are conducting an internal investigation and say they will share their findings by Friday with the Baltimore state's attorney for possible prosecution. It is not known when or if those findings will be made public. The U.S. Justice Department is also investigating, as is the Gray family attorney.